1. Field of the Invention
The present invention relates to a device for adjusting an attitude of a sphere comprising a protruded portion on a surface in order to remove the protruded portion, for example.
2. Description of the Related Art
A golf ball is usually formed by upper and lower molds having hemispherical cavities, respectively. An injection molding method, a compression molding method or the like is employed for a molding method. By any molding method, the slight leakage of a molding material (rubber, synthetic resin or the like) from a parting line of the upper and lower molds cannot be avoided. Accordingly, a ring-shaped spew is generated on a portion corresponding to the parting line on the surface of the formed golf ball (which will be hereinafter referred to as a “seam”). In the injection molding method, a gate is provided on the parting line of a mold. The spew is also generated in a portion corresponding to the gate. These spews are to be removed.
The spew can be removed by devices disclosed in Japanese Unexamined Patent Publications Nos. Sho 60-232861, Sho63-174801, Sho 63-11266 and Hei 8-229810. In these devices, the spew is caused to abut on a cutting tool and is thus removed while a chucked golf ball is rotated. A grindstone, a sandpaper, a cutter blade or the like is used for the cutting tool. It is necessary to maintain the positional relationship between the spew and the cutting tool to be constant during the rotation of the golf ball. More specifically, the golf ball is to be chucked in such a manner that a plane including a seam and a rotating axis are orthogonal to each other. The golf ball is usually chucked in order to maintain the seam to be horizontal. The adjustment of the attitude of the golf ball to be carried out for the chucking has formerly been executed by a manual work. This work has a poor efficiency and the manufacturing cost of the golf ball is increased.
Japanese Unexamined Patent Publication No. Sho 59-81059 has disclosed a device for mechanically adjusting the attitude of a golf ball to cause a seam to be horizontal without depending on a manual work. FIG. 7(a) is a perspective view showing a part of an attitude adjusting device 101 and FIG. 7(b) is a plan view showing the same part. The attitude adjusting device 101 comprises a pair of rollers 103. A golf ball G having a spew B is mounted on the rollers 103. The rollers 103 rotate in a direction shown in an arrow of FIG. 7(a). By the rotation, the golf ball G is rolled. A pair of stoppers 105 are provided above the rollers 103. The spew B abuts on the stoppers 105 so that the rolling of the golf ball G is stopped. In a stoppage stage, the spew B becomes horizontal. The golf ball G is transported to a cutting step with this attitude maintained.
The golf ball G is spherical and the roller 103 is cylindrical. Therefore, the contact area of the golf ball G and the roller 103 is small. With the roller 103, kinetic force cannot be fully transmitted to the golf ball G. In the device 101, the golf ball G is insufficiently rolled. In some cases in which the rolling is insufficient, the spew B does not abut on the stopper 105 within a predetermined time so that the golf ball G is transferred to the cutting step without the horizontal spew B. If the spew B is not horizontal, it is not completely removed or a portion other than the spew B on the surface of the golf ball G is cut.
There has been proposed a device for deciding whether the spew B is horizontal prior to the cutting step. In this device, a golf ball having the spew B decided to be nonhorizontal is returned to the attitude adjusting device 101. By the return, a defective ball can be prevented from being generated. The return having a high rate deteriorates the productivity of the golf ball G.